Identification of Novel Genetic Risk Factors for Focal Segmental Glomerulosclerosis in Children: Results From the Chronic Kidney Disease in Children (CKiD) Cohort

Identification of GTF2I Polymorphisms as Potential Biomarkers for CKD in the Han Chinese Population : Multicentric Collaborative Cross-Sectional Cohort Study

Key Points

Genetic factors are key players in CKD, with two linked single-nucleotide polymorphisms in the GTF2I gene, associated with CKD susceptibility in the Taiwanese population. Individuals with specific GTF2I genotypes (CT/TT for rs117026326 and CT/CC for rs73366469) show higher CKD prevalence and earlier onset. Men with the specific genotypes of rs117026326 and rs73366469 face a heightened CKD risk compared with women, particularly at lower eGFR.

Background

CKD poses a global health challenge, but its molecular mechanisms are poorly understood. Genetic factors play a critical role, and phenome-wide association studies and genome-wide association studies shed light on CKD's genetic architecture, shared variants, and biological pathways.

Methods

Using data from the multicenter collaborative precision medicine cohort, we conducted a retrospective prospectively maintained cross-sectional study. Participants with comprehensive information and genotyping data were selected, and genome-wide association study and phenome-wide association study analyses were performed using the curated Taiwan Biobank version 2 array to identify CKD-associated genetic variants and explore their phenotypic associations.

Results

Among 58,091 volunteers, 8420 participants were enrolled. Individuals with CKD exhibited higher prevalence of metabolic, cardiovascular, autoimmune, and nephritic disorders. Genetic analysis unveiled two closely linked single-nucleotide polymorphisms, rs117026326 and rs73366469, both associated with GTF2I and CKD (r 2 = 0.64). Further examination revealed significant associations between these single-nucleotide polymorphisms and various kidney-related diseases. The CKD group showed a higher proportion of individuals with specific genotypes (CT/TT for rs117026326 and CT/CC for rs73366469), suggesting potential associations with CKD susceptibility (P < 0.001). Furthermore, individuals with these genotypes developed CKD at an earlier age. Multiple logistic regression confirmed the independent association of these genetic variants with CKD. Subgroup analysis based on eGFR demonstrated an increased risk of CKD among carriers of the rs117026326 CT/TT genotypes (odds ratio [OR], 1.15; 95% confidence interval [CI], 1.07 to 1.24; P < 0.001; OR, 1.32, 95% CI, 1.04 to 1.66; P = 0.02, respectively) and carriers of the rs73366469 CT/CC genotypes (OR, 1.13; 95% CI, 1.05 to 1.21; P < 0.001; OR, 1.31; 95% CI, 1.08 to 1.58; P = 0.0049, respectively). In addition, men had a higher CKD risk than women at lower eGFR levels (OR, 1.35; 95% CI, 1.13 to 1.61; P < 0.001).

Conclusions

Our study reveals important links between genetic variants GTF2I and susceptibility to CKD, advancing our understanding of CKD development in the Taiwanese population and suggesting potential for personalized prevention and management strategies. More research is needed to validate and explore these variants in diverse populations.

Nephrotic Syndrome Throughout Childhood: Diagnosing Podocytopathies From the Womb to the Dorm

The etiologies of podocyte dysfunction that lead to pediatric nephrotic syndrome (NS) are vast and vary with age at presentation. The discovery of numerous novel genetic podocytopathies and the evolution of diagnostic technologies has transformed the investigation of steroid-resistant NS while simultaneously promoting the replacement of traditional morphology-based disease classifications with a mechanistic approach. Podocytopathies associated with primary and secondary steroid-resistant NS manifest as diffuse mesangial sclerosis, minimal change disease, focal segmental glomerulosclerosis, and collapsing glomerulopathy. Molecular testing, once an ancillary option, has become a vital component of the clinical investigation and when paired with kidney biopsy findings, provides data that can optimize treatment and prognosis. This review focuses on the causes including selected monogenic defects, clinical phenotypes, histopathologic findings, and age-appropriate differential diagnoses of nephrotic syndrome in the pediatric population with an emphasis on podocytopathies.

Pharmacogenomics: A Genetic Approach to Drug Development and Therapy

The majority of the well-known pharmacogenomics research used in the medical sciences contributes to our understanding of medication interactions. It has a significant impact on treatment and drug development. The broad use of pharmacogenomics is required for the progress of therapy. The main focus is on how genes and an intricate gene system affect the body's reaction to medications. Novel biomarkers that help identify a patient group that is more or less likely to respond to a certain medication have been discovered as a result of recent developments in the field of clinical therapeutics. It aims to improve customized therapy by giving the appropriate drug at the right dose at the right time and making sure that the right prescriptions are issued. A combination of genetic, environmental, and patient variables that impact the pharmacokinetics and/or pharmacodynamics of medications results in interindividual variance in drug response. Drug development, illness susceptibility, and treatment efficacy are all impacted by pharmacogenomics. The purpose of this work is to give a review that might serve as a foundation for the creation of new pharmacogenomics applications, techniques, or strategies.

Temporal trends in prevalence and disability of chronic kidney disease caused by specific etiologies: an analysis of the Global Burden of Disease Study 2019

BACKGROUND

The prevalence of disability in CKD is high. In this context the aim of the present study was to assess the  temporal trends of prevalence and disability progression for chronic kidney disease (CKD) caused by specific etiologies.

METHODS

Using data from the Global Burden of Diseases Study (GBD) 2019, we examined the age-standardized rates of CKD prevalence and disability-adjusted life-years for different etiologies, including Type 1/2 diabetes mellitus (T1DM/T2DM), glomerulonephritis, and hypertension. We also calculated the average annual percentage changes to assess trends. Additionally, we utilized the joinpoint regression model to identify significant shifts over time.

RESULTS

From 1990 to 2019, the global prevalence of CKD due to various etiologies exhibited an overall increasing trend, albeit with fluctuations. Notably, CKD due to T1DM, glomerulonephritis, and hypertension consistently demonstrated a significant upward trend across all continents, while the prevalence of CKD due to T2DM varied across continents. In terms of disability-adjusted life-years, CKD due to T2DM and hypertension exhibited a significant rising trend over the past 30 years. However, changes in age standardized disability-adjusted life-years for CKD due to different etiologies were not consistent across continents, with an upward trend observed in The Americas and a contrasting trend in Asia. Furthermore, both age-standardized prevalence rate and age standardized disability-adjusted life-year trends for CKD varied significantly across 204 countries and territories. Additionally, a negative association was observed between the Socio-demographic Index and the disability progression of CKD.

CONCLUSION

The prevalence and disability burden of CKD caused by specific etiologies show substantial heterogeneity worldwide, highlighting significant disparities in the distribution of CKD. It is crucial to implement geographic and personalized strategies in different regions to alleviate the burden of CKD effectively.

Insights into human kidney function from the study of Drosophila

Biological and biomedical research using Drosophila melanogaster as a model organism has gained recognition through several Nobel prizes within the last 100 years. Drosophila exhibits several advantages when compared to other in vivo models such as mice and rats, as its life cycle is very short, animal maintenance is easy and inexpensive and a huge variety of transgenic strains and tools are publicly available. Moreover, more than 70% of human disease-causing genes are highly conserved in the fruit fly. Here, we explain the use of Drosophila in nephrology research and describe two kidney tissues, Malpighian tubules and the nephrocytes. The latter are the homologous cells to mammalian glomerular podocytes and helped to provide insights into a variety of signaling pathways due to the high morphological similarities and the conserved molecular make-up between nephrocytes and podocytes. In recent years, nephrocytes have also been used to study inter-organ communication as links between nephrocytes and the heart, the immune system and the muscles have been described. In addition, other tissues such as the eye and the reproductive system can be used to study the functional role of proteins being part of the kidney filtration barrier.

Genes, environment, and African ancestry in cardiometabolic disorders

The past two decades have been characterized by a substantial global increase in cardiometabolic diseases, but the prevalence and incidence of these diseases and related traits differ across populations. African ancestry populations are among the most affected yet least included in research. Populations of African descent manifest significant genetic and environmental diversity and this under-representation is a missed opportunity for discovery and could exacerbate existing health disparities and curtail equitable implementation of precision medicine. Here, we discuss cardiometabolic diseases and traits in the context of African descent populations, including both genetic and environmental contributors and emphasizing novel discoveries. We also review new initiatives to include more individuals of African descent in genomics to address current gaps in the field.

Role of Alström syndrome 1 in the regulation of glomerular hemodynamics

Inactivating mutations in the ALMS1 gene in humans cause Alström syndrome, characterized by the early onset of obesity, insulin resistance, and renal dysfunction. However, the role of ALMS1 in renal function and hemodynamics is unclear. We previously found that ALMS1 is expressed in thick ascending limbs, where it binds and decreases Na+-K+-2Cl- cotransporter activity. We hypothesized that ALMS1 is expressed in macula densa cells and that its deletion enhances tubuloglomerular feedback (TGF) and reduces glomerular filtration rate (GFR) in rats. To test this, homozygous ALMS1 knockout (KO) and littermate wild-type Dahl salt-sensitive rats were studied. TGF sensitivity was higher in ALMS1 KO rats as measured by in vivo renal micropuncture. Using confocal microscopy, we confirmed immunolabeling of ALMS1 in macula densa cells (nitric oxide synthase 1 positive), supporting a role for ALMS1 in TGF regulation. Baseline glomerular capillary pressure was higher in ALMS1 KO rats, as was mean arterial pressure. Renal interstitial hydrostatic pressure was lower in ALMS1 KO rats, which is linked to increased Na+ reabsorption and hypertension. GFR was reduced in ALMS1 KO rats. Seven-week-old ALMS1 KO rats were not proteinuric, but proteinuria was present in 18- to 22-wk-old ALMS1 KO rats. The glomerulosclerosis index was higher in 18-wk-old ALMS1 KO rats. In conclusion, ALMS1 is involved in the control of glomerular hemodynamics in part by enhancing TGF sensitivity, and this may contribute to decreased GFR. Increased TGF sensitivity, enhanced glomerular capillary pressure, and hypertension may lead to glomerular damage in ALMS1 KO rats. These are the first data supporting the role of ALMS1 in TGF and glomerular hemodynamics.NEW & NOTEWORTHY ALMS1 is a novel protein involved in regulating tubuloglomerular feedback (TGF) sensitivity, glomerular capillary pressure, and blood pressure, and its dysfunction may reduce renal function and cause glomerular damage.